1. Field of the Invention
This invention relates to a method of interconnecting two members and to an assembly comprising two interconnected members, the planar members or the planar parts of the members being in parallel spaced apart relationship with respect to each other. The method and assembly can have various applications.
2. Description of the Prior Art
Welding is at present the commonest procedure for providing a permanent assembly comprising two planar metal members or items, for example two sheet metal blanks, in parallel spaced-apart relationship with respect to each other. Normally cross-members or bracing members, which can be of a variety of forms, are welded between the two members to be assembled. Such a procedure is not only expensive but can cause stress and distortion in the members when assembled.
Another alternative is to use screws or screw-threaded rods which engage in apertures in the two items or members and which are used in combination either with tubular cross-members or bracing members, which are disposed between the two items to be assembled and have the screws or rods extending therethrough or with nuts which are secured to the screws or rods on either side of the two items. In the former, the cost of the items required for assembly are, as in the previous case, fairly high, as is also the case when rivets are used instead of screws or screw-threaded rods in combination with the tubular cross-members.
Also, the diameters of the screws, threaded rods and rivets depend upon the dimensions, and in particular the thickness, of the items to be assembled, so that narrow screws or rods or rivets have to be used for sheet metal parts. Consequently, tubular cross-members or bracing members through which the screws or threaded rods or rivets extend are also of reduced diameter. The resulting system is of reduced strength, particularly as regards its ability to prevent a pivoting or tilting movement of one of the assembled items relative to the other. To provide a strong connection of this kind between two items which extend appreciably along two axes, a number of screws or rods or rivets must be distributed over the area of items -- that is, a large number of assemblies must be provided. For instance, to assemble two elongate section members, for example of channel section, in spaced-apart relationship with respect to one another to form a composite beam, by way of their webs at least two longitudinal rows of screws or rods or rivets are necessary if the beam is to be of adequate strength.